Corona Santiago linebacker Jordan Walker is at Loma Linda University Medical Center with a spinal injury, Coach Jeff Steinberg said.
A hospital spokeswoman said Walker was in critical condition.
Walker, a junior, was injured in the first quarter on Friday night in an Inland Division quarterfinal playoff game against Upland. Upland won, 30-29.
"Our thoughts and prayers are with him and his family," Steinberg said.
Steinberg was scheduled to visit the hospital on Saturday morning.